Edmund Clerihew Bentley (1875-1956) was a man of many accomplishments. He was a mystery writer, (Trent's Last Case) scholar, and journalist. He is most distinguished though as the creator of the clerihew, a form of humorous verse that has been assigned his middle name. The verse about Sir Humphry Davy in Tem42's write up was Bentley's first one written while he was in secondary school. Bored with chemistry class one day he composed the poem to imprecate the famous chemist, Sir Humphrey Davy (1778-1892), who is the discoverer of potassium, calcium, and sodium. Here's another example:

George the Third

    George the Third
    Ought never to have occurred.
    One can only wonder
    At so grotesque a blunder.

George the Third was a monarch in British history who became infamous for a long string of blunders: waging war against the American Independent Movement led by George Washington; meddling with the French Revolution for a prolonged period of time; denying equal opportunities to the Catholic Church; and refusing any ideas about reform.

Similar to, but more complicated than limericks, a good definition that I've read regarding clerihews comes from the Poets' Corner. The best ones have most of these elements in common:

http://www.geocities.com/~spanoudi/poems/

It takes a certain knack to achieve a good clerihew; just the right amount of drollery with a soft touch of humor along with an intimate personal knowledge about the target. But with practice they they can be an entertaining challenge. One night for Halloween I secretly prepared homemade headstones with clerihews about my family and decorated the front yard with them, one said:

    Number One Son
    was out having fun
    Forgot to do his chores
    And is no more.

You can see that the clerihew has the potential of a lot of whimsy and usually very little malice. The next morning it was great fun to peek out the window and see the wry grins from family and neighbors giggling as they got up and went on their way to work and school. Here are some more of these entertaining little verses written by Edmund Clerihew Bentley from his book Biography for Beginners .


Sir Christopher Wren
John Stuart Mill
Clive
    What I like about Clive
    Is that he is no longer alive.
    There is a great deal to be said
    For being dead.

Edward the Confessor
Chapman & Hall
    Chapman & Hall
    Swore not at all.
    Mr Chapman's yea was yea,
    And Mr Hall's nay was nay.

Bentley published three collections of clerihews: Biography for Beginners appeared in October 1905, More Biography in 1929 and Baseless Biography in 1939. These publications went onto establish the form and its name by inspiring later well known writers, including W.H. Auden, William Jay Smith and Roy Blount, Jr.

Sources:

Clerihews:
http://thinks.com/words/clerihew.htm

It's hard to precisely define a clerihew:
www.geocities.com/~bblair/000710f.htm

Public domain text taken from The Poets’ Corner:
http://www.theotherpages.org/poems/bentley1.html#1

CST Approved.